G.Kleinschmidt said:
I can't move the amp from the bench yet, to my real big fullrange speakers uppstairs. I haven't finished mainconnections and a backplate for support of the big capacitors. So, I use some small shitty speakers from a cheap ministereo to test with. I also don't have any preamplifier so I can't get it to clip from just the CD player.
Anyway, it behaves perfectly well so far. I have also done testing with a green eye EM84. I now also have to fix 185V for that baby.
Everything takes time. I'm also in a shoal of repairwork for a music store's amplifiers and mixers at the moment. Next week I will do progress so that I can move this baby around to some decent speakers. I will not move the descent speakers down to the cellar 😱 It's crowded down there allready. It's a Mecka for an electronic nerd though
Some more progress (I never get finished 
)
Because I saved my box to this amp from the scrapheap I had to do new front and backplates in aluminum. I can cut and get them for free where I work. (The stylish "gold" front with engraving has to wait for now)
After some drilling and milling I have now managed to put nearly everything in place. (The EM84 eye is still waiting to be mounted)
So, what happened with the listeningtests upstairs where "the descent" speakers is?
It was done yesterday evening together with some nice wine, so the glorious audio shimmering was even better then best 😀
First of all the amp is now very silent when it should be. I don't know exactly whats happened but it seems that when I put the back and front on and attached the large electrolyths bolts to the backplane (they have internal connection to the minuspole) the small 100hz Frrrr.. disappeared
I have also changed the 30volt baby transformer for the HV. to the tubes. This is a 15-0-15 which gives 35 volts instead of 27Volt from the one i first used. I now have about 108volts on the anodes.
I can't get the amp to clip just from the CD or the RIAA phonoamp when playing vinyl. so I did some cheating using my Equalizer with all frequencies upped, just to see how loud I can get before my 10 watts is at max. I know I have pretty sensitive speakers but I was surprised how loud and clean this little amp can be 😎 There where some ringing in the ears just after a small maxed out session 😉
I have a couple of CD's I know very well and was surprised I heard some tunes in a different way. There was experiences like "Oh did that voice sound like that before" and "that trumpet I havent heard so prominent before. I can't say for sure because I know that comparing two things and not be able to do it with switching A - B can be misleading, but this amplifier definately plays music really good.
Many audiophiles wrinkle one's nose when they get told that there is a large capacitor before connection to spekers. But if no one tell them and also don't show them the schematic (which they probably don't understand anyway) they would say that this amp doesn't sound at all.... it just put the music trough without coloration.
I use Sanyo capacitors and Jamicon elyths at the outputs. High quality industry components used in switched PSU's. I have not used any "audiofile grade" component.
I post to dark and shitty pictures this time. I have to do some better later on, maybe on my homepage.
Next time I will have some measuring Data showing up. I will use The RMAA (Right Mark Audio Analyzer)
Have a nice weekend.
)Because I saved my box to this amp from the scrapheap I had to do new front and backplates in aluminum. I can cut and get them for free where I work. (The stylish "gold" front with engraving has to wait for now)
After some drilling and milling I have now managed to put nearly everything in place. (The EM84 eye is still waiting to be mounted)
So, what happened with the listeningtests upstairs where "the descent" speakers is?
It was done yesterday evening together with some nice wine, so the glorious audio shimmering was even better then best 😀
First of all the amp is now very silent when it should be. I don't know exactly whats happened but it seems that when I put the back and front on and attached the large electrolyths bolts to the backplane (they have internal connection to the minuspole) the small 100hz Frrrr.. disappeared
I have also changed the 30volt baby transformer for the HV. to the tubes. This is a 15-0-15 which gives 35 volts instead of 27Volt from the one i first used. I now have about 108volts on the anodes.
I can't get the amp to clip just from the CD or the RIAA phonoamp when playing vinyl. so I did some cheating using my Equalizer with all frequencies upped, just to see how loud I can get before my 10 watts is at max. I know I have pretty sensitive speakers but I was surprised how loud and clean this little amp can be 😎 There where some ringing in the ears just after a small maxed out session 😉
I have a couple of CD's I know very well and was surprised I heard some tunes in a different way. There was experiences like "Oh did that voice sound like that before" and "that trumpet I havent heard so prominent before. I can't say for sure because I know that comparing two things and not be able to do it with switching A - B can be misleading, but this amplifier definately plays music really good.
Many audiophiles wrinkle one's nose when they get told that there is a large capacitor before connection to spekers. But if no one tell them and also don't show them the schematic (which they probably don't understand anyway) they would say that this amp doesn't sound at all.... it just put the music trough without coloration.
I use Sanyo capacitors and Jamicon elyths at the outputs. High quality industry components used in switched PSU's. I have not used any "audiofile grade" component.
I post to dark and shitty pictures this time. I have to do some better later on, maybe on my homepage.
Next time I will have some measuring Data showing up. I will use The RMAA (Right Mark Audio Analyzer)
Have a nice weekend.
Good work Radioman 🙂
You're doing better that me! I blew one channel a month or two ago when doing some measurements (mulitmeter probe slipped) and its just been sitting unfinished since.
Your little 100Hz buzz was just killed by the better shielding of the assemble case, I'd guess.
I also run (ran) mine with sensitive speakers. With sensitive speakers it has been my experience that so long as an amplifer is stable and clips / recovers from overload cleanly, you can get a surprisingly loud level of subjectively clean audio with rather little power.
I'm a bit surprised that you can't get the amplifier to clip with the output from your CD player though. A little under 1V rms input is required to produce rated output.
If you need more gain R20 can be increased in value.
Cheers,
Glen
You're doing better that me! I blew one channel a month or two ago when doing some measurements (mulitmeter probe slipped) and its just been sitting unfinished since.
Your little 100Hz buzz was just killed by the better shielding of the assemble case, I'd guess.
I also run (ran) mine with sensitive speakers. With sensitive speakers it has been my experience that so long as an amplifer is stable and clips / recovers from overload cleanly, you can get a surprisingly loud level of subjectively clean audio with rather little power.
I'm a bit surprised that you can't get the amplifier to clip with the output from your CD player though. A little under 1V rms input is required to produce rated output.
If you need more gain R20 can be increased in value.
Cheers,
Glen
Yes, I also measured 1volt RMS at the bench for clipping. Even todays almost overdriven CD titles comes close but not enough, to my ears anyway. I will soon install my green eye to help me 😀
Another thing. I can't get half the supply between upper and lower part of amp. I mean it clips unsymetrically. Negative before positive.
I have about 31.3 Volt over the endstage but just about 14.5 Volt at the grid leg 7. I havent tested with adjusting the bias. Would maybe change it? Tell an amateur whats going on please 🙁
Another thing. I can't get half the supply between upper and lower part of amp. I mean it clips unsymetrically. Negative before positive.
I have about 31.3 Volt over the endstage but just about 14.5 Volt at the grid leg 7. I havent tested with adjusting the bias. Would maybe change it? Tell an amateur whats going on please 🙁
Enough of this BORING amp stuff...!!!
How's this for a class A cutie? 😀
Check out those toobs!
🙂🙂🙂🙂🙂
How's this for a class A cutie? 😀
Check out those toobs!
An externally hosted image should be here but it was not working when we last tested it.
🙂🙂🙂🙂🙂
Radioman62 said:
The amp does clip a little earlier on the negative swing. I left it this way because it gives a little extra headroom from the ripple on the 30V rail if someone runs theirs with smaller supply rail filter capacitance, but at the end of the day it probably wouldn't make much difference anyway.
If it still bugs you, you can bring the bias point up by lowering the value of R2.
MJL21193 said:
Ermm......
How may beers have you had John?
Cheers,
Glen
Hi Glen, your boards arrived yesterday... your e-mail button is not showing....
My computer decided to selfdestruct big time... so I no longer have your e-mail address either to send you a thank you note...
The package will stay unopened for the next two weeks until after the move... if I open it now I'll just be distratcted from all the work ahead of me...
It will be my first project in the new workshop 🙂 Thank you once again... You are a star.
I'm just glad to have a new PC again... and not so glad about the new debt...
My computer decided to selfdestruct big time... so I no longer have your e-mail address either to send you a thank you note...
The package will stay unopened for the next two weeks until after the move... if I open it now I'll just be distratcted from all the work ahead of me...
It will be my first project in the new workshop 🙂 Thank you once again... You are a star.
I'm just glad to have a new PC again... and not so glad about the new debt...
Nordic said:
He was getting too much fan mail maybe?
🙂
Glen, I'm getting through a few of my other projects and expect to complete my build before Christmas (nice present to myself from myself).
Still lacking the 30vac transformer.
I know you have been waiting with bated breath.🙄
Magic eye completed
Hi all amp builders
I just wanna brag with some more progress 😱
I'm finished with the EM84 installation. Another baby transformer back to back connected to the first one.
Anybody interrested in the schematic I can show you here if you want.
I'll throw two teasing pictures at you. Next time I will have some measuring figures I hope 🙂
How many PCB's did you sell Glen?
Sure there is someone more that can show some progress with this cute amplifier.
Hi all amp builders
I just wanna brag with some more progress 😱
I'm finished with the EM84 installation. Another baby transformer back to back connected to the first one.
Anybody interrested in the schematic I can show you here if you want.
I'll throw two teasing pictures at you. Next time I will have some measuring figures I hope 🙂
How many PCB's did you sell Glen?
Sure there is someone more that can show some progress with this cute amplifier.
Looks great Ove!
How does it sound? What are the speakers that you are using?
I'm not even close to finished with mine. I don't have a pair of nice efficient speakers to use with it - a future project, no doubt.
Looks good.
How does it sound? What are the speakers that you are using?
I'm not even close to finished with mine. I don't have a pair of nice efficient speakers to use with it - a future project, no doubt.
Looks good.
Re: Magic eye completed
Hi Ove
20 pairs or so.
You're the only one who has reported on an operational pair.
Cheers,
Glen
Radioman62 said:How many PCB's did you sell Glen?
Sure there is someone more that can show some progress with this cute amplifier.
Hi Ove
20 pairs or so.
You're the only one who has reported on an operational pair.
Cheers,
Glen
Thanks JohnMJL21193 said:Looks great Ove!
How does it sound? What are the speakers that you are using?
I'm not even close to finished with mine. I don't have a pair of nice efficient speakers to use with it - a future project, no doubt.
Looks good.
I use some old speakers I built myself about 16 years ago. Modded with some, now classical, vintage oil cooled Dynaudio tweeters later on. Its 3 way 5" middle and double 10" basses. About 100 liter closed boxes. I don't have the data but 92-96 dB one meter.
For the moment I use some real small monitor speakers that sound quite impressive for their size. I bought them at a HiFi exhibition two weeks ago. Dynavoice Magic S-4 EX
Today I also dis some measuring with the Rightmark tool I mentioned earlier.
I did a -1.5dB loop trough test. The only difference between audiocard and the amp was that the Kleinschmidt had 8 ohm resistive loads. The card burst out a sinewave in half second bursts every two seconds or something as the testsignal to adjust levels
It seemed to be about 3.5 volt p-p so thats not near 0dB, is it ? Anyway the results are on this link Maybe I can get better sn. ratio at higher volume? Crosstalk is not the strongest either. I havent done any real serious test with this setup before so I can't compare. I have to tests some more amps so i know if I can be satisfied with these figures. Anyway, the amplifier sounds really good and the distorsion comes on smoth when it clips.
Radioman62 said:
Nice speakers. How do they sound?
The measurement that you took don't look right. They show Glen's amp making an unholy racket!
Did you use a high output impedance attenuator for the soundcard input from the amp?
Here are measurements I made of the patchwork amp. Sorry, no graphs remain.
Attachments
Right John
I used no attenuation at all at the output. Just trimmed the input volume (from the schematic) so that the output would be in par with input level.
I can see that it's not fair.
Is it fair to put out maybe 1 or 3 watt in 8 ohm and then attenuate it to be in par with the output at the soundcard?
Does the attenuators impedance influate that much on the results?
Which effect did you measure at in your tests above?
I used no attenuation at all at the output. Just trimmed the input volume (from the schematic) so that the output would be in par with input level.
I can see that it's not fair.
Is it fair to put out maybe 1 or 3 watt in 8 ohm and then attenuate it to be in par with the output at the soundcard?
Does the attenuators impedance influate that much on the results?
Which effect did you measure at in your tests above?
Radioman62 said:
I think I used an voltage divider/attenuator with an output impedance of ~100 ohms. I tested the amp above at nearly full power - 140 watts.
I just measured the output before I connected it to the soundcard. There is always a risk, and I burned out one soundcard already.
Testing
Hi John
Is your amp that sensitive that you can get full effect, I mean clipping with the audiocards signal level, with just the audiocards output ?
Hi John
Is your amp that sensitive that you can get full effect, I mean clipping with the audiocards signal level, with just the audiocards output ?
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